Qizhong Lin

activity

20242026

collaborators

9 papers

math.CO2026

The logarithmic exponent of the Ramsey number $r (4, t)$

Qizhong Lin, Qiuyang Zhang

We prove that $r (4, t) \geq \frac{t ^{3}}{( l o g t ) ^{2 + o (1)}}$ . This improves the lower bound of Mattheus and Verstraëte (Ann. of Math., 2024) by a factor of $(lo g t)^{2 - o (1)}$ .

math.CO2026

Ordered Ramsey numbers of 3-uniform hypergraphs with bounded weak degeneracy

Wen Chen, Zihan He, Qizhong Lin +1

The \emph{ordered Ramsey number} $r_{<} (G, H)$ of ordered $k$ -graphs $G$ and $H$ is the least integer $N$ such that every red-blue edge-coloring of the naturally ordered complete $k$ -…

math.CO2026

Hypergraph Erdős--Rogers functions with consecutive clique sizes

Qizhong Lin, Lin Niu

For integers $k\le s<t$, the hypergraph Erdős--Rogers function $f^{(k)}_{s,t}(n)$ is the largest integer $m$ such that every $n$-vertex $K_t^{(k)}$-free $k$-graph conta…

math.CO2025

Ramsey numbers of long even cycles versus books

Qizhong Lin, Shixi Song

For any positive integers $k$ and $n$ , let $B_{n}^{(k)}$ be the book graph consisting of $n$ copies of the complete graph $K_{k + 1}$ sharing a common $K_{k}$ . Let $C_{m}$ be a cycle of le…

math.CO2025

Asymptotically optimal Ramsey goodness of sparse graphs versus odd cycles and paths

Chunchao Fan, Qizhong Lin

A fundamental problem in graph Ramsey theory is to determine, for sparse graphs $G$ on $n$ vertices, the minimal $n$ such that $G$ is Ramsey-good for odd cycles $C_{k}$ and paths $P_…

math.CO2025

The Ramsey number of the 4-cycle versus a book graph

Chunyang Dou, Tianyu Li, Qizhong Lin +1

Given positive integers $n$ and $k$ , the book graph $B_{n}^{(k)}$ consists of $n$ copies of $K_{k + 1}$ sharing a common $K_{k}$ . The book graph is a common generalization of a star and…

math.CO2025

Phase transitions of the Erdős-Gyárfás function

Xinyu Hu, Qizhong Lin, Xin Lu +1

Given positive integers $p, q$ . For any integer $k \geq 2$ , an edge coloring of the complete $k$ -graph $K_{n}^{(k)}$ is said to be a $(p, q)$ -coloring if every copy of $K_{p}^{(k)}$ receive…

math.CO2024

New bounds of two hypergraph Ramsey problems

Chunchao Fan, Xinyu Hu, Qizhong Lin +1

We focus on two hypergraph Ramsey problems. First, we consider the Erdős-Hajnal function $r_{k} (k + 1, t; n)$ . In 1972, Erdős and Hajnal conjectured that the tower growth rate of $r_k(k+…

math.CO2024

A step towards the Ramsey-Turán conjecture for $K_{3}$ and $K_{6}$

Xinyu Hu, Qizhong Lin

Ramsey-Turán type problems were initiated by Erdős and Sós in 1969. Given integers $p, q \geq 2$ , a graph $G$ is $(K_{p}, K_{q})$ -free if there exists a red/blue edge coloring of $G$ such…

The logarithmic exponent of the Ramsey number r(4,t)

Ordered Ramsey numbers of 3-uniform hypergraphs with bounded weak degeneracy

Hypergraph Erdős--Rogers functions with consecutive clique sizes

Ramsey numbers of long even cycles versus books

Asymptotically optimal Ramsey goodness of sparse graphs versus odd cycles and paths

The Ramsey number of the 4-cycle versus a book graph

Phase transitions of the Erdős-Gyárfás function

New bounds of two hypergraph Ramsey problems

A step towards the Ramsey-Turán conjecture for K3​ and K6​

The logarithmic exponent of the Ramsey number $r (4, t)$

A step towards the Ramsey-Turán conjecture for $K_{3}$ and $K_{6}$